Around 260 billion cans are produced every year world wide. A single production line can make up to 500,000,000 cans per year in a continuous process from aluminium or steel strip. As an example, a cup, pressed from the metal sheet, is formed into the can body in one continuous punch stroke in about one fifth of a second, forming the inside diameter of about 66 mm, and increasing the height from 33 to 57 mm, then, through three ironing rings, to stretch the wall to 130 mm high, before forming the concave dome at the base of the can.
Due to the very tight tolerances required for the tooling (±0.002 mm) to keep the correct can dimensions, the alignment of the punch with respect to the ironing rings and dome die is critical.
The manufacture of cans is a continuous process and therefore a reliable and predictable service life between servicing is essential.
U.S. Pat. No. 5,736,658 discloses a component of tooling preferably used in the deep-drawing of aluminium and steel cans. The tooling is comprised of a nickel-bonded cemented carbide. However, as no cobalt is added to the binder phase, the grade is non-magnetic, which could be a critical drawback for the can maker that requests magnetic materials for the punch tool, and furthermore has a very low WC content to obtain a material with low density.
WO 2008/079083 discloses a punch tool of a cemented carbide containing tungsten carbide, titanium carbide, niobium carbide, cobalt and chromium together with other possible additions.